import { describe, expect, it, vi } from "vitest";
import {
  createAbortableFetchMock,
  createJsonResponse,
} from "./internal/test-builders.test-support.js";
import { createDiscordRequestClient, DISCORD_REST_TIMEOUT_MS } from "./proxy-request-client.js";

async function expectAbortError(promise: Promise<unknown>) {
  let abortError: unknown;
  try {
    await promise;
  } catch (error) {
    abortError = error;
  }
  expect(abortError).toBeInstanceOf(DOMException);
  if (!(abortError instanceof DOMException)) {
    throw new Error("expected Discord request abort error");
  }
  expect(abortError.name).toBe("AbortError");
  expect(abortError.message).toBe("The operation was aborted.");
}

describe("createDiscordRequestClient", () => {
  it("preserves the REST client's abort signal for proxied fetch calls", async () => {
    const fetchSpy = vi.fn(async (_input: string | URL | Request, init?: RequestInit) => {
      if (!(init?.signal instanceof AbortSignal)) {
        throw new Error("Expected proxied fetch init to include an AbortSignal");
      }
      expect(init.signal.aborted).toBe(false);
      return createJsonResponse([]);
    });

    const client = createDiscordRequestClient("Bot test-token", {
      fetch: fetchSpy as never,
      queueRequests: false,
    });

    await client.get("/channels/123/messages");
    expect(fetchSpy).toHaveBeenCalledTimes(1);
  });

  it("lets the REST client abort hanging proxied requests after its timeout", async () => {
    const { fetch: fetchSpy } = createAbortableFetchMock();

    const client = createDiscordRequestClient("Bot test-token", {
      fetch: fetchSpy as never,
      queueRequests: false,
      timeout: 20,
    });

    await expectAbortError(client.get("/channels/123/messages"));
  }, 1_000);

  it("lets abortAllRequests cancel active proxied fetches", async () => {
    const abortable = createAbortableFetchMock();

    const client = createDiscordRequestClient("Bot test-token", {
      fetch: abortable.fetch as never,
      queueRequests: false,
      timeout: 5_000,
    });

    const request = client.get("/channels/123/messages");
    await vi.waitFor(() => expect(abortable.fetch).toHaveBeenCalledTimes(1));

    client.abortAllRequests();

    await expectAbortError(request);
    if (!abortable.receivedSignal) {
      throw new Error("Expected proxied fetch abort signal");
    }
    expect(abortable.receivedSignal.aborted).toBe(true);
  });

  it("provides the REST client's timeout signal even without a caller signal", async () => {
    let receivedSignal: AbortSignal | undefined;

    const fetchSpy = vi.fn(async (_input: string | URL | Request, init?: RequestInit) => {
      receivedSignal = init?.signal ?? undefined;
      return createJsonResponse({});
    });

    const client = createDiscordRequestClient("Bot test-token", {
      fetch: fetchSpy as never,
      queueRequests: false,
    });

    await client.get("/channels/123/messages");

    if (!receivedSignal) {
      throw new Error("Expected proxied fetch to receive the REST timeout signal");
    }
    expect(receivedSignal.aborted).toBe(false);
  });

  it("exports a reasonable timeout constant", () => {
    expect(DISCORD_REST_TIMEOUT_MS).toBeGreaterThanOrEqual(5_000);
    expect(DISCORD_REST_TIMEOUT_MS).toBeLessThanOrEqual(30_000);
  });
});